An electric clutch actuator (ECA) controls engagement and disengagement of a clutch. For instance, the clutch connects an engine to a transmission of a vehicle powertrain when engaged and disconnects the engine from the transmission when disengaged. The ECA receives power for controlling the clutch from a battery. At times, the level or amount of battery power to the ECA may be too low or too high. The battery power may become too low as a result of loss of battery connection while the ECA is in a motoring mode. Likewise, the battery power may become too high as a result of loss of battery connection while the ECA is in a regeneration mode. Timely detection of such battery power failure of the ECA in either case is desirable.